ICPMSMS

ICPMSMS, short for inductively coupled plasma tandem mass spectrometry, is an analytical technique that combines an inductively coupled plasma ion source with a tandem mass spectrometer to enable highly selective and sensitive elemental analysis at trace levels. It is typically implemented as an ICP-QQQ-MS, using three mass filters: first quadrupole (Q1), a collision/reaction cell in the middle, and a second quadrupole (Q3) for analysis of product ions.

In operation, Q1 selects precursor ions based on their mass-to-charge ratio. These ions enter the collision/reaction cell, where they undergo chemical reactions or collisions with neutral gas molecules (for example O2, H2, NH3, or CH4). The resulting product ions or transformed species then pass to Q3, which filters for the desired product ions before detection. This configuration allows selective suppression or elimination of interferences, including polyatomic species and isobaric overlaps, by exploiting reaction chemistry or kinetic discrimination.

The method offers advantages such as improved selectivity, lower backgrounds, and better detection limits compared with single-quadrupole systems. It is particularly beneficial for challenging analyses where interferences limit accuracy, and it enables certain isotope ratio measurements and speciation studies when coupled with chromatographic separation.

Common applications span environmental monitoring (trace metals in water, soil, and sediments), food safety (containment of toxic metals), clinical and biomedical analyses (trace element profiling), and semiconductor or materials analysis. While ICPMSMS provides enhanced performance, it involves higher instrument complexity, operating costs, and more intricate method development and maintenance, including management of the reactive gas environment.